This invention relates to can ends and, more particularly to a beverage can end having a concentric lipped-spout opening for drinking or pouring the contents of the can.
Can ends having central openings are known to the art, as described in my U.S. Pat. No. 4,244,490. As disclosed therein, a centered conical frustum was drawn in the can with the apex end forming an orifice. That patent also discloses a pushdown gate in the apex of the cone such as the triplefold gate disclosed in U.S. Pat. No. 3,334,775 to myself and Kenneth E. Harper. Other types of cans having conical ends with crown or cap closures have been used and are desirable because they have drinking and pouring characteristics comparable to bottles.
As beverage cans became popular and widespread, flat top ends gradually dominated the market. Economic packaging and manufacturing factors were largely responsible for this. At first, the cans were opened with can openers but at present most cans are provided with an eccentric opening near the edge of the can end. These edge openings are gated by pull tabs or push-in tabs and the common type, now in general use, is a lever operated push-in tab.
The present ends, having lever operated push-in tabs, are unsatisfactory for a number of reasons including consumer dissatisfaction and a high manufacturing cost.
The improved end unit, drawn from a flat metal material, as herein disclosed, was conceived and developed to overcome the disadvantages of the present ends. The advantages and objectives of this improved end unit are designed to provide a can end having a concentric convenience opening which has better drinking and pouring characteristics, which has a better appearance for a beverage can, and which has a pushdown gate in the aperture arranged to permit the can to be held and opened with one hand.
A further important objective is to reduce the cost of can ends and the present invention can reduce this cost by as much as 40 percent.
First, there is a significant reduction in metal usage. Beverage cans 2 11/16 inches in diameter are presently necked in at the top to a diameter of 2 6/16 inches (206 industrial designation), which is the maximum reduction practicable with lever-operated openings in the ends. The reason for necking is to permit a reduced diameter of the end unit in order to save metal. This, in turn, permits a reduction in the thickness of the metal forming the unit. The present invention, an end with the centered opening, permits a significant further reduction in the diameter of the top of the can body, with a further reduction of end diameter and thickness. The present industrial necking machinery is capable of necking a can body down to a 2-inch diameter opening. The improved end may be used with this 2-inch diameter opening or even a smaller opening with modified necking machinery. A further reduction in metal usage is effected in elimination of the levers per se and this elimination of levers permits a reduction in the end unit countersink depth. Altogether, the present invention permits metal usage reduction in four areas affecting a metal cost savings of more than 25 percent.
Secondly, in addition to metal usage savings, a 10 to 15 percent savings is possible in manufacturing costs. The manufacture of the improved concentric ends is greatly simplified because a single press is required as opposed to the present 2-press systems. The cost of tooling is greatly reduced because all components are concentric and tooling can be produced with ordinary machine shop equipment in contrast with the special machines needed to produce the present eccentric tooling. In addition to being less costly, concentric tooling is more durable.
Thirdly, much wider tolerances are permissible with the improved end than are permissible with the present lever operated eccentric opening ends. For example, the score depths on the present ends must be held to very close tolerances. The score depth tolerance on the improved end is so great as to be of no special consideration. Altogether, this simplification of the manufacturing process results in improved manufacturing reliability with its consequent spoilage reduction, reduction in maintenance down time, and an increase in quality level assurance.
Fourthly, it is to be noted that the improved end may be manufactured from either aluminum or steel as opposed to present convenience opening ends which can be manufactured only of aluminum.